Several routine measures in molecular biology involve monitoring and/or controlling the population density of bacterial colonies grown in liquid medium by withdrawing samples and measuring turbidity. The purpose of this project is to develop a system to continuously monitor cell population by measuring associated changes in optical properties of the culture. Current work is aimed at determining the feasibility of such techniques for short term study (8 hours). Current and future effort will be directed at determining and improving the long term stability (several days) of the tansducer, improving the noise characteristics of the system, and developing the capability for simultaneous monitoring of multiple channels (32).